Extension attachment for boats



Nov. 27,1951 E. s. ANDERSON EXTENSION ATTACHMENT FOR BoATs Filed JulyE 24', 194'? m mf C@ balanced.

owner of an outboard motor boat wishes to utiit at higher speeds.

Patented Nov. 27, 1951 lSTATES PATENT oFFicE EXTENSION ATTACHMENT FOR BOATS EmilfS. Anderson, Chicago, Ill. AApplication July 24, 1947, Serial No. 763,254

l. The invention relates to an attachment for the hull of a power driven boat and particularly la boat driven by an outboard motor.

rvHulls for outboard motors are built by certain builders while the motors are manufactured by other manufacturers'. Because of this fact, a purchaser of a hull .and motorrarely obtains a combination thereof in which the two are truli7 It also frequently occurs that Vthe lize a heavier and more powerful motor on a hull that is primarily designed for a lighter, less powerful motor. Such a hull with the heavier motor obviously will not give good performance, particularly when an attempt is made to operate Longitudinal oscillation or porpoising may occur aS well as lack of stability and other difficulties. i

-The general object of theinvention is therefore to provide an attachment for such a hull,

which has the effect of dampening such longitudinal vibration and adds materially to the running stability of the boat, particularly in the casevwhere a relatively heavy, powerful motor is utilized.

More specifically, it is an object of the invention to provide an extension, in the form of a readily applied attachment for the hull of a boat used with an outboard motor, the extension providing anincrease in the effective length of the hull, thus gaining the advantage of a larger hull.

Another object is to provide an extension of the foregoing general character, which is adjustable to the most effective operating position for a given combination of hull and motor.

A further object is to provide an extension of the foregoing character, which may be so related to the hull bottom as to give it the advantages of the so-called step-bottom hull.

Other objects and advantages will become apparent from the following description, taken in with the' t- 3 claims. (C1. 114-665) 2 i f which is truly balanced and coordinated with the motor used with such hull. Also, such an owner may frequently attempt to use amotor which is much more powerful and heavier than the hull is primarily designed for. The present invention provides an attachment for such a hull which has the effect of lengtheningthe hull and thereby dampening tendencies of the hull to undergo longitudinal oscillation or porpoising when driven by such a, high-powered motor. .The present attachment also provides a means whereby adjustment thereof may bring the hull into a reasonably balanced relation with the motor so that the two cooperate with the maximum effect. The present device further provides attainment of the beneficial effects of the so-called stepbottom hull.

Generally described, the attachment comprises ya plate-like structure adapted to be attached to the transom of the hull which constitutes, in effect, an extension of the bottom of the boat. The plate-like structure is angularly adjustable relative to the hull so that the mosteffective operating. position may be obtained. The attachment of the plate-like structure to the hull is also so placed as to give the step-bottom effect.

In the drawing, I have shown a boat, the hull of which is indicated generally at I0 andwhich includes a transom l l. No particular boat structure is claimed, but it may be stated that the type illustrated is one which is frequently used with outboard motors. Mounted on the transom by meansfof a clamp, as is usual, is an outboard motor, indicated generally, at I2, the propeller shaft casing of the motor extending downwardly so that the propeller, indicated at I3, is below the bottom of the hull.

The hull bottom, when the boat is operating at substantial speed, provides a planing action tending to lift the boat and causing it to operate more or less at the surface of the water. With a motor which is of higher power than that for which the hull isprimarily designed, longitudinal vibration or porpoising of the hull may occur at substantial speeds. This is largely due to the length of the planing surface or bottom of the boat in relation to the power of the motor and speed of operation thereof. A longer hull would, of course, eliminate such diiculty, but actual elongation ofthe hull itself would be diflicult, if not impractical to attain.

The present device is in the form of an attachment which may be readily applied to the transom Il to give the effect of increased length to the hull. Tok this end, I provide a plate structure,

indicated generally at 20, attached to the transom l I adjacent the bottom edge thereof and extending rearwardly therefrom. The plate structure thus operates substantially as a continuation of the bottom of the boat to give =the eifect of increased length. Because the motor l2' is mounted directly on the transom Il, the plate structure is provided centrally with an opening or gap to permit ythe propeller drive to extend downwardly therethrough. In the present instance, I have found it simpler -t make the plate structure 20 in the form of two separate plates 2l mounted on opposite sides of the propeller shaft casing. In its preferred form, ea'eh plate 2l is of Vsuiilcient area so that it extends from a point near the longitudinal center lirr f the boat laterally, substantially to the side vedge of the boat. The two plates 2l thus together form a continuation of the bottom of the boat eiicept for the central -area between the plates through which the propeller drive casing of the motr extends.- Each plate 2| is held in position by being attached at its front edge to the transom and having a brace, indicated generally at 22, attached at its' front eiid to the transom and at its rear end to the Plate adjacent the rear edge thereof. Infoider teI permit the plate structure to -be adaptable to different hulls and different motors with the idea of obtaining the best conditions of bal-'aime for each, I provide for adjustment of the plate structure lin its angular relation to the bottoni of the hull.Y Te this end, while the angulaiity of the plate might be varied by making it oi relatively flexible metal, I have shown the plates 2| as being secured to the transom at their front edges by means of hinges 23. The braces are also made adjustable so as to be able to swing the plate 2l en its hinges 23. In the present instance, each brace 22 is in the form of an inverted Y with the ends of 'the arms of the Y pivotally secured to the plate 2l adjacent the rear edge thereof byl means of brackets 24. The stern of the Y'is' pivotally secured tothe transom Il by meafns o'ffa bracket 25 spaced upwardly from the hinges 2'3. The' stein ofthe Y isalseA madeV ex` tensible by means f a telescoping Structure 'comprising a tubular portion 26 and 'a rod 2 slldably mounted therein and pivoted on thebracket 25. A setscrew 28 may be' provided for holding the tubular portion 26 and ro'd 21 rigidly in adjusted position. To' gain the step-bottom effect, the hinges 23 are spaced a short distance above the bottom edge of the transom Il so that the front edge of the plates 2| thus forni a step with the bottoni or .the hun. y

The attachment above described may be readily secured to the transom of the boat merely byv screws ortho like'. After placing such attachon the boat, the preferred angular position of the' plates 2l may be determined-by trial. Thus, the tel-escorting construction of the' braces' z-l Ymay be adjusted to diirerent positions until the position-is found where longitudinal vibrations or porpoising are reducedto a minimum. The attaehnient` is relatively light in weightand tense duently'does not add-greatly to the overal-1 weight of the hull, but it does have the effect of providing a' substantial incre-ase in the planing ao'e er bottom of the hull. The attachment thus' profvides a simple means .for adapting, motors of vafious sizes to a given hull structure. A

I claim:

1. An attachment for an outboard motor boat Y of the type having a substantially flat bottom and a transom extending upwardly from the rear edge of the bottom, said attachment comprising a pair of plates adapted to extend rearwardly from the transom on opposite sides of the motor adjacent the bottom of the boat and providing a plane surface constituting an extension of the bottom, lihge means mounted att-h frnt edge of said plates for 'pivotlly connecting th plates to the Vadjusted to attain longitudinal balance for' the 2. In an outboard motor boatof the type having a substantially flat bottom and a transom eX- tending upwardly from the rear edge of .the bottom, an attachment comprising a plate structure adapted to extend rearwardly `from the transom with its front edge spaced above the bottom of Y the boat to provide a stepped bottom effecti and means for connecting the plate structure tothe transom including adjustable bracing means `for varying the angular relation of the plate strueture to the bottom of the boat whereby to attain longitudinal balance for the boat. y 3i In .an outboard motor boat of the type having a substantially iiat bottom and a transom extending upwardly from the rear edge ofthe bottom, an attachment comprising a plate struc'- ture adaptedto extend rearwardly from the transom, means for attaching Said plate structure to the transom with the front edge of saidplate structure spaced above the bottom of the boatfto provide a stepped lbottom eiect, and adjustable bracing means connected to the transom and to said plate structure adjacent the opposite side edges of the latter for varying the angular .relation of the If'late structure to the bottom ofthe boat whereby to attain longitudinal balance for the boat. ,V

Y EMIL S.- MJDERSQNl itaiiiiitNCTEs Ciiiiii Y The following references are er record in the nie er :this patent; Y

" oT'nERi REFERENCES The Beat Boor," Popular Chicago (1935), page25i. 

